High prevalence of hepatitis B nonimmunity in vaccinated pediatric liver transplant recipients.

Durable protection from hepatitis B virus (HBV) and other vaccine-preventable diseases assumes great importance due to improved long-term patient and graft survival rates in pediatric liver transplantation. Vaccine immunogenicity data in transplanted children is limited. This was a cross-sectional, single-center, point-prevalence study evaluating HBV immunity in 160 pediatric liver transplant recipients. Patients with hepatitis B surface antibody levels <10 IU/L were considered nonimmune. Predictor variables for nonimmunity identified in univariate analyses were later analyzed within a logistic regression model. All subjects received the full HBV vaccination series prior to transplant. The majority (67%) of previously immunized pediatric liver transplant patients were nonimmune. Older children (p < 0.001) and children who were further out from transplant (p < 0.001) were more likely to be nonimmune in univariate analyses, but only time from transplant was a significant predictor of nonimmunity in a logistic regression model (odds ratio 1.3, p < 0.001 at 1 year). The mean time since transplant was 5.6 years ± 4.6. Markers of nutrition, immunosuppression, white blood cell parameters and type/severity of disease did not correlate with HBV immunity. Information on the anamnestic response to boosting or revaccination is needed to adequately address this vulnerable group.

Outpatient cold knife tonsillectomy in toddlers with sleep disordered breathing.

PROBLEM: Tonsillectomy performed as day surgery has become popular over the last fifteen years. However, there are conflicting opinions regarding the safety of this practice, especially in children of very young age. We sought to determine the safety of outpatient tonsillectomy in children aged three years old and younger. METHODOLOGY: A retrospective study of all tonsillectomies performed in a major pediatric hospital during a two-year period was conducted. Age, gender, indication for tonsillectomy, other procedures performed simultaneously, seniority of operating surgeon, and reasons for hospital admissions during the first post-operative week were recorded. Patients with inappropriate records for the analysis were excluded. A total of 1058 patients were studied. Tonsillectomized children were divided into two age groups: greater than 3 years old (n = 951) and 3 years old or younger (n = 107). RESULTS: Male gender, obstructed sleep disordered breathing as indication for surgery, seniority of the operating surgeon, and age of 3 years old or younger were not associated with post-operative complications. CONCLUSIONS: Outpatient tonsillectomy can be managed safely regardless of age, as long as specific factors, such as good recovery room supervision, exist.

Outcomes and efficacy of newborn hearing screening: strengths and weaknesses (success or failure?).

OBJECTIVE: To assess the outcomes of neonatal hearing screening with regard to the final diagnosis in a very large number of newborns and investigate related strengths and weaknesses of the program. SUBJECTS: In this study, 76,560 newborns were assessed. METHOD: All neonates were assessed using transient evoked otoacoustic emissions (TEOAEs). RESULTS: From the 76,560 neonates screened, 1,564 (2%) failed the test. According to the screening protocol, all parents of failed neonates were asked to bring their children 1 month following discharge to repeat the test. Of the 541 (34.6%) newborns who repeated the test, 303 (56%) were found normal and 238 (44%) again failed TEOAE. The latter children were referred to two special public centers for full audiology evaluation. In addition, 124 neonates were also referred due to other reasons revealed in the screening process (family history, high levels of bilirubin, etc.). Of the 362 children who were referred to the two special audiology centers, 113 (31.2%) were evaluated by these two centers. In addition, 42 children who had failed initial screening and did not show up for a follow-up appointment to repeat TEOAE were also assessed in the same centers. Of the 155 children who had a special audiologic evaluation, 56 (36.1%) were found to have hearing loss (HL) and 99 (63.9%) normal hearing. In detail, 28 had bilateral sensorineural HL greater than 40 dB, 10 had unilateral sensorineural HL greater than 40 dB, and 18 had otitis media with effusion or other conductive HL. CONCLUSIONS: Derived from the present study: 1) repeated testing of "failed" newborns in the maternity hospital and before discharge leads to an acceptable referral rate of 2%; 2) the 1-month follow-up of "failed" newborns further limits the false positive results but leads to high rate of newborns lost to follow-up; 3) a dedicated secretariat system should be implemented to follow-up each "failed" newborn and remind parents about their follow-up appointments; and 4) additional measures such as detailed educational material and parental friendly approach should also be implemented.

Prelingual nonsyndromic hearing loss in Greece. Molecular and clinical findings.

Mutations in the gene encoding the gap-junction protein connexin 26 (GJB2) on chromosome 13q11 have been shown as a major contributor to prelingual, sensorineural, nonsyndromic deafness. One specific mutation, 35delG, has accounted for the majority of the mutations detected in the GJB2 gene in Caucasian populations and is one of the most frequent disease mutations identified so far with highest carrier frequency of 3,5% in the Greek population. In a collaboration with the major referral centers for childhood deafness in Greece, patients were examined by an extensive questionnaire to exclude syndromic forms and environmental causes of deafness and by allele-specific PCR for the detection of the 35delG mutation. The 35delG mutation was found in 32.1% of the alleles in 173 unrelated cases of prelingual deafness: 50 homozygotes and 11 heterozygotes. Individuals heterozygous for the 35delG mutation were further analyzed by direct genomic sequencing of the coding region of the GJB2 gene, which revealed R184P and 486insT mutations in single alleles. We conclude that the 35delG GJB2 mutation is responsible for one third of prelingual, sensorineural deafness in Greece, which is higher than the usually quoted 20% for Caucasian populations.

Information processing by parafoveal cells in the primate nucleus of the optic tract.

We recorded from single units in the pretectal nucleus of the optic tract (NOT) of the nonhuman primate. Specifically, we examined units that are modulated during smooth tracking of a small laser spot against a dark background. We used a nonlinear optimization procedure to determine whether the unit responses of these parafoveal cells are better described by a model that incorporates retinal error motion parameters or by a model that incorporates eye motion parameters. Our main finding was that all the cells in our sample group were better fit with a three-component model that incorporated retinal error motion parameters of position, velocity and acceleration (average coefficient of determination = 0.84) than a model that used position, velocity and acceleration components of eye motion (average coefficient of determination = 0.68). Other analyses involved comparison of goodness of fit between the three-component retinal error model and two-component retinal error models that excluded position or acceleration related terms. We found that there was a statistically significant degradation in the fit when position and acceleration related terms were dropped from the retinal error based model (P<0.05). Unit data from experiments in which the laser spot was extinguished for a brief period of time during tracking showed that the unit response was decreased following the target blink. We conclude on the basis of this and previous experimental data and our dynamic modeling approach that the parafoveal cells in the NOT primarily encode retinal error motion. Further they encode position, velocity and acceleration components of retinal error that could be used by other downstream structures for synthesis of a smooth-pursuit eye movement.

A study on the otoscopical and audiological findings in patients with Down's syndrome in Greece.

One hundred and twenty patients (children) with Down's Syndrome were examined by the Audiological Dept. at 'Aghia Sophia' Children's Hospital during the period 1988-1990. Of these 73 (60.8%) were boys and 47 (37.2%) were girls. Their ages varied from 7-18 years of age with an average age of 14.8 years. Physical examination included otoscopy, tympanometry, and in some cases auditory brainstem audiometry. It is worth noting that a high percentage of these patients were unable to cooperate in this study, therefore making it obligatory to utilize objective measures for hearing evaluation.

The in-house computer for the orthodontic office.

Increased labor costs and reduced computer costs have made the in-house computer system for the orthodontic office a reality that is both cost effective and efficient. Six years of research have been devoted to development of the correct handware and software combination that will harmonize with the staff personnel available in the routine orthodontic environment.